Improvement in rheostats or resistance-coils



GEORGE LITTLE.

nt in Rheostats Ior Resistance Coils.

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Specification forming part of Letters Patent No. 122,267, dated December 26, 1871.

T0 all 107mm 'it 'may concern:

Be it known that l, GEORGE LITTLE, ot' Rutherlord Parli, in the county ot' Bergen and State ot New Jersey, have invented an improvement in ltheostats or tesistance-Goils for Telegraph purposes; and the following is declared to be a correct description ot the same.

/ This invention relates to a rheostat or resistance instrument that is adapted to telegraph operations, where the current is to be divided or its i'orce regulated. This is ei'ected by a sliding block and spring' that connects the parts, so that more or less ot' a coil of insulated Wire is brought into the electric circuit, thereby regulating the resistance to the current.

This instrument is shown in connection with a chemical telegraph for the purposes of illustration.

In the drawing, Figure .l is a plan of the rheostat instrument7 illustrating also the position thereotI in the main line and the shunt to the chemical telegraph; and Fig. 2 is a vertical longitudinal section ot' said rheostat instrument.

The heads a. and Y) are connected to each other by a tube oi'l hard rubber, c, or other non-conducting material, and around this is Wound tightly a coil, c, ot' insulated Wire, the ends being in metallic connection with the heads a and b. The.

non-conducting covering ot' the Wire c is caused to adhere in place or harden by heat or otherwise, and then the surface is dressed oli' to eX- pose the Wires Without injuring the insulation. The main line Wires f and g connect with the respective heads c b, so that the pulsations of electricity would have to go through the entire coil c, it no other means were employed 5 thereby there would be a. considerable resistance to the current. l however employ a movable conductor, 7s, that brings more or less of the coil c into action. The rod l is in metallic contact with the head (l, but insulated in the head D; and upon this rod l is a sliding block, m, carryinglthe conductor is, the end ot' which rests upon the coil c, and the metallic contact is insured by a spring, o, in the block m, between the rod Z and conductor is.

The rod l being insulated, thc electricity cannot pass from the head I) to the conductor 7c, ex-

cept through the coil c, and according to the distance the conductor 7ris from the head b so the resistance will be more or less. The irires 1J q, passing from the heads c I), lead to the chemical telegraph a-pi'mratns and i'orin the shunt or derived circuit, and the pen or stilus r and cylinder s for chemically-prepared paper illustrate this well-known character of telegraph apparatus.

I claim as my invention- The conductor 7;, sliding block m, and spring o, in combination with the coil e, heads a b, and bar l, substantially as and for the purposes set forth.

Signed by me this 23d day of August, A. D.V

GEORGE LITTLE. Witnesses:

(J1-Ins. H. SMITH,

GEo. T. PINCKNEY. (50) 

